Engineering Commons^™

Real-Time Method For Calculating Retardation Functions, Li-Hao Yuan, Yue-Sheng Ma, Ying-Fei Zan, Zhao-Hui Wu

Journal of Marine Science and Technology

To meet the demand for real-time calculation of time-domain motion equations, a state-space model was established to replace the convolution integral method to improve computational efficiency. On the basis of the HYSY201 vessel, the impulse response curve fitting method and the realization theory method based on the time-domain identification theory were compared to establish the state-space model. The results of roll decay simulation conducted using the state-space model and the convolution integral method were verified against decay test results. The simulation results for retardation function, radiation forces, and motion time histories calculated using the state-space model and the convolution integral …

Modeling Of A Head - Neck Assembly Drop Tower Impact Test Using Abaqus, Hussein Sharqi Owaid

Electronic Theses and Dissertations

There are numerous potential causes of traumatic brain injury (TBI) and concussions, including traffic accidents, contact during sports and falls. Protection from these injuries is paramount because of the problems that result from TBI, such as loss of thinking and memory capability. Head impact from falls, especially in elderly, can also result in severe to fatal injury and some effects of brain injury are often not visible. For these reasons and more a need exists for protective head gear that can keep persons safe during at risk physical activity and that can protect fall prone persons from accidental injuries. Part …

Experimental Assessment Of Suspended Sediment Concentration Changed By Solitary Wave, Jae-Nam Cho, Chang-Geun Song, Kyu-Nam Hwang, Seung-Oh Lee

Journal of Marine Science and Technology

A large scale solitary wave causes a lot of sediment transportation and coastal beach erosion, for example tsunami is the one type of solitary waves. During passing such solitary wave over coastal region, higher energy on sediment transportation near bottom would bring to massive geomorphological changes and even worse damages in life and economics. The major objective of this study is to analyze the incipient motion of sediment suspended from bottom by a solitary wave through hydraulic experiments and numerical simulations. First, to estimate the process of sediment transport the experimental study was carried out in the prismatic rectangular channel …

Investigation Of Effects Of Wave Directions On Hull Wave Loads By Hydroelastic Experimental Method, Zhanyang Chen, Jialong Jiao

Journal of Marine Science and Technology

This paper focuses on the hydroelastic responses of ultralarge vessels under different wave directions. Segmented ship model experiments provide an invaluable tool in naval applications. However, most model tests are performed on heading waves. Therefore, a segmented model with variable cross-section steel backbones was designed and the oblique wave tests were performed in a comprehensive test tank. The oblique wave test system was introduced in detail. Time histories of bending moments in oblique waves were given. In order to analyze the influence of structural elastic effect on hydroelastic responses, the number of segments of the model was changed, and the …

Determination Of Vertical Datum Level For Tidal Bench Mark Using Gnss Buoy Observations, Jae Young Roh, Kyung Wan Yoo, Yong Cheol Suh, Moon Seung Shin, Dong Ha Lee

Journal of Marine Science and Technology

Coastal areas are the most vulnerable areas to sea level fluctuations. Such areas comprise approximately 4% of South Korea's total land; therefore, monitoring these fluctuations is crucial. The present study determined the vertical datum level using a global navigation satellite system (GNSS). Unlike traditional sea level measurements, which are performed using fixed-type gauge observations, a GNSS has an accuracy of a few millimetres and no spatiotemporal constraints. For this purpose, a set of buoys containing GNSS devices was installed in coastal waters, and observations were performed for more than 8 h. The processed GNSS buoy data were compared with tidal …

Simulation And Motion Analysis Of Deepwater Manifold Lifting, Zhiwei Chen, Tingdi Zhao, Jian Jiao, Dongfeng Mao

Journal of Marine Science and Technology

The development and utilization of oil and gas resources has expanded to deep water. The installation of a subsea manifold is crucial for developing offshore oil-gas fields. In this study, we used the lifting installation method (LIM) to install a subsea manifold. First, the appropriate environmental parameters were selected through the analysis of environmental loads at the Liwan 3-1 Gasfield in the South China Sea. The wind and wave spectra were selected using noise power density and Joint North Sea Wave Project spectra, respectively. The entire lifting and installation system that responds to environmental loads comprised a vessel, cable, and …

Dynamic Response Analysis Of Micro-Grid With Ocean Thermal Energy Conversion, Chia-Yu Hsu, Ming-Wang Chen, Pei-Hwa Huang

Journal of Marine Science and Technology

The main purpose of this paper is to analyze the dynamic responses of micro-grid with Ocean Thermal Energy Conversion (OTEC) system. The power sources of the studied micro-grid system include an OTEC generator and a wind generator. Three different types of OTEC generation systems, i.e., open-cycle, closed-cycle, and hybrid-cycle, are considered, under the conditions with the same temperature of sea water and output of generator. When the system operates in an islanding or gridconnected mode, the responses subject to load variation are quite different. As the system operates in the grid-connected mode, the voltage and frequency are less affected by …

Cyclic Shear Behavior Characteristics Of Marine Silty Sand, Su Won Son, Min Jae Ko, Jin Man Kim

Journal of Marine Science and Technology

Owing to the high demand for energy supply, the use of offshore wind turbines as a renewable and environment-friendly energy source has been remarkably increased. After installation in the ocean, the offshore structure foundations and soil that support them are subjected to cyclic loading from wind and waves. In this study, laboratory experiments were conducted to evaluate the shear behavior characteristics of the marine soil subjected to cyclic loading. Utilizing a cyclic direct simple shear (CDSS) test apparatus, the undrained shear failure behavior of marine silty sand was investigated. The results show that the cyclic behavior and permanent shear strain …

Research On Integration And Sharing Solutions For Big Structured Data For The Marine Environment, Wei Wang, Wenfang Cheng, Jing Chen, Ya-Nan Yu, Jianxun Zhang

Journal of Marine Science and Technology

The data-intensive science, a new paradigm in scientific discovery, demands an urgent solution to integrate and share big marine environment data. Through the modeling of marine environmental features (such as Temperature, Salinity, Density et al.), a novel solution is presented in this paper. This solution employs Hadoop and Hbase, based on the Bigtable algorithm first proposed by Google Inc. By using hierarchical technology, scalability of the data integration framework is realized. Additionally, an efficient execution of various queries is realized by using the customized auxiliary index algorithm. In the experimental cluster environment constructed from four ordinary personal computers, experiments involving …

The Nonlinear Dynamics And Anti-Sway Tracking Control For Offshore Container Crane On A Mobile Harbor, You-Gang Sun, Hai-Yan Qiang, Junqi Xu, Da-Shan Dong

Journal of Marine Science and Technology

The offshore container crane (OCC), as a novel maritime container transfer system, can handle container from a large container-ship anchored in open sea to address the congestion and limited water-depth of port. However, for the wave- and wind-induced movements of the ship, the crane's control system should be redesigned to ensure the load transfer on the sea. In this paper, we derive the nonlinear dynamic equations of OCC system subjected to the ship motions based on dynamic analysis. Then a double-layer sliding manifold is constructed to realize the position tracking and sway control simultaneously, irrespective of ship motions and parameters …

Energy Efficient Trajectory Design For The Underwater Vehicle With Bounded Inputs Using The Global Optimal Sliding-Mode Control, Mai The Vu, Hyeung-Sik Choi, Jin-Il Kang, Dae-Hyung Ji, Hyun Joong

Journal of Marine Science and Technology

In this paper, we propose a novel global sliding mode controller (SMC) for an uncertain linear time-varying second order system. The proposed controller was implemented on the underwater vehicle (UV) with uncertainty of bounded parameters and disturbances within limited control input. By applying the proposed controller to the second-order UV system, the arrival time at the reference position and the maximum allowable acceleration are expressed in a closed-form equation if ranges of parametric uncertainties and reference inputs are specified. The closed-form equation can be utilized in designing the capacity of vehicle systems with the condition of the minimum arrival time …

A Numerical Model For Pipeline Abandonment In Deep Water, Duanfeng Han, Kuo Huang, Yingfei Zan, Zhaohui Wu

Journal of Marine Science and Technology

In offshore oil and gas engineering, pipeline abandonment is unavoidable and its mechanical analysis is necessary and important. For this problem, a numerical model is developed in this study to evaluate pipeline abandonment for the J-laying method. The whole system considered in this model is divided into two parts: the A&R cable and the pipeline in the water. A catenary model was proposed for the former, and the latter is solved by a numerical iterative method. In addition to the boundary conditions at the two end points, a special set of boundary conditions is required at the junction that connects …

A Time-Domain Numerical Tool For A Wave Energy Attenuator With The Sph Method, Da-Wei Chen, Shuichi Nagata, Shiaw-Yih Tzang, Yasutaka Imai, Chih-Min Hsieh, Jiahn-Horng Chen

Journal of Marine Science and Technology

The wave energy attenuator is a floating device which operates perpendicular to the wave fronts and captures wave energy from the relative motions of two hinged floaters as waves passing by them. For establishing the time-domain numerical tools to evaluate the performance of a wave energy attenuator, a Smoothed Particle Hydrodynamic (SPH) model with mesh-free method was adopted to simulate the hydrodynamic behaviors of each floating object. Three different wave heights of 6 cm, 7 cm, and 10.4 cm of the same period of 1.22 s were commonly derived from typical potential oceanic zones offshore Taiwan and Japan. Comparisons of …

Production Of Bio-Oil With Different Oxygen Content And Characterization Of Catalytic Upgrading To Transportation Fuel, Mubarak Mohammed Khlewee

Electronic Theses and Dissertations

The world’s increasing population requires an increase in transportation fuel production. The lack of production of transportation fuels due to the shortage of fossil fuel resources combined with concerns about global emissions of carbon dioxide from fossil fuel combustion are the two major issues that have driven researchers to actively pursue alternative sources for oil production. Biomass is being considered as an alternative feedstock to produce fuel and chemicals due to its abundance and renewability. It has many features that make it suitable as a source of transportation fuel production. However, the bio-oil produced by the fast pyrolysis process has …

Dynamic Modeling And Extreme Tension Analysis Of Mooring System For A Floating Offshore Wind Turbine, Wei Ting Hsu

Electronic Theses and Dissertations

For offshore wind industry, exploiting the dynamic behaviors of mooring lines is of increasing importance in floating offshore wind turbine (FOWT) mooring system design. Currently, the design philosophy for structures and moorings is based on principles and practices adopted in offshore oil and gas, including mooring systems that are optimized for applications in deeper waters. However, the design of FOWT mooring systems is facing several challenges, including installation costs, the stability of light-weight minimalistic platforms, and shallow water depths (50-300m). The extreme tension in mooring lines of a light displacement platform in shallow water is dominated by snap loads. Hence …

Development Of In Vitro Drug Screening Platforms Using Human Induced Pluripotent Stem Cell-Derived Cardiovascular Cells, Yosuke Kurokawa

McKelvey School of Engineering Theses & Dissertations

Drug-induced cardiotoxicity is a critical challenge in the development of new drugs. Since the advent of human pluripotent stem cell-derived cardiomyocytes (CMs), researchers have explored ways to utilize these cells for in vitro preclinical drug screening applications. One area of interest is microphysiological systems (i.e. organ-on-a-chip), which aims to create more complex in vitro models of human organ systems, thus improving drug response predictions. In this dissertation, we investigated novel analysis methods and model platforms for detecting drug-induced cardiotoxicity using human induced pluripotent stem cell (iPSC)-derived cardiovascular cells.

First, we utilized human iPSC-derived CMs (iPS-CMs) to establish optical methods of …

Reconstruction Algorithms For Novel Joint Imaging Techniques In Pet, Homayoon Ranjbar

McKelvey School of Engineering Theses & Dissertations

Positron emission tomography (PET) is an important functional in vivo imaging modality with many clinical applications. Its enormously wide range of applications has made both research and industry combine it with other imaging modalities such as X-ray computed tomography (CT) or magnetic resonance imaging (MRI). The general purpose of this work is to study two cases in PET where the goal is to perform image reconstruction jointly on two data types.

The first case is the Beta-Gamma image reconstruction. Positron emitting isotopes, such as ¹¹C, ¹³N, and ¹⁸F, can be used to label molecules, and tracers, such …

Characterizing Anisotropy In Fibrous Soft Materials By Mr Elastography Of Slow And Fast Shear Waves, John Larson Schmidt

McKelvey School of Engineering Theses & Dissertations

The general objective of this work was to develop experimental methods based on magnetic resonance elastography (MRE) to characterize fibrous soft materials. Mathematical models of tissue biomechanics capable of predicting injury, such as traumatic brain injury (TBI), are of great interest and potential. However, the accuracy of predictions from such models depends on accuracy of the underlying material parameters. This dissertation describes work toward three aims. First, experimental methods were designed to characterize fibrous materials based on a transversely isotropic material model. Second, these methods are applied to characterize the anisotropic properties of white matter brain tissue ex vivo. Third, …

The Inter-Laminar Shearing Effect On Wrinkle Development In Composite Forming Processes, David Sundquist

McKelvey School of Engineering Theses & Dissertations

Composite materials are becoming prevalent in aerospace industries as the uniqueness of the composite structure allows the composite to be tailored specifically for individual applications. Many fabrication techniques produce defects in composite parts such as wrinkles, fiber waviness, fiber misalignment, and porosity. The driving mechanisms behind these defects occurring during forming processes are not fully understood and, thus, characterization formation of these defects in a uncured state is beneficial to optimize composite processing. This work primarily investigated the influence of how uncured pre-impregnated carbon ply properties affect the wrinkling behavior of a composite laminates. Several factors affecting composite ply forming …

Development Of A Curriculum Analysis And Simulation Library With Applications In Curricular Analytics, Michael S. Hickman

Electrical and Computer Engineering ETDs

Higher education institutions are currently investing significant resources in attempts to improve student success by improving instruction quality, implementing tutoring programs, and providing other services to help students. While these are all worth- while, one area that tends to be overlooked is the structure of the curricula that are offered. When viewing curricula as data, or more specifically, a graph, it is intuitive to see how its structure can influence a student’s ability to move through it. How- ever, there are currently no tools to analyze a curriculum’s structural properties and how they might affect student success. This thesis describes …

Co-Simulation Framework For Power Distribution System Analysis With Humans In The Loop, Victor H. Ayon

Mechanical Engineering ETDs

Recent developments in the area of power generation have led to an increased penetration of storage and distributed energy resources (DER) in power distribution systems. As a result, new and enhanced energy management systems will be necessary as the deployment of DERs, as well as the need to control loads, continues to increase in the coming years. Advanced management systems are especially important to achieve resilient power delivery during emergency situations. During a blackout for example, a section of a distribution feeder could island to operate as a microgrid to ensure critical services such as water, food, and medical care …

The Future Of Nuclear Security: A Medical Physicist’S Perspective, Katharine E. Thomson

International Journal of Nuclear Security

Planning for the future of nuclear security is a vital and complex task, requiring cooperation and contribution from many disciplines and industries. This diversity of expertise should include the medical sector, which faces many of the same challenges as the nuclear industry: controlling access to dangerous material, creating a strong security culture, cooperating with the wider world and engaging the public.

Medical physicists, of which the author is one, oversee all aspects of small-scale radiation use. This paper discusses three key areas increasingly important to both medical and nuclear uses of radioactive materials: public engagement, prevention of nuclear and radiological …

Assessing And Enhancing Nuclear Safety And Security Culture For Small Facilities That Handle Radioactive Material, Solymosi Máté

International Journal of Nuclear Security

The use of radioactive sources is expanding all over the world and abreast the necessity of the enhancement of its safe and secure application is increasing too. In the nuclear industry, the safety and security are top priorities since decades. They share the same goal, to protect humans from the negative affect of the ionizing radiation. The human component of them is a significant factor and technical solutions can protect us so far and thus the culture for safety and security become a major focus. On the other hand, there are still some contradiction between recommendations and international guidance of …

The Future Of Nuclear Security In Moroccan Territory After The Creation Of The New Moroccan Agency Of Nuclear And Radiological Safety And Security: Opportunities And Challenges, Amal Touarsi, Amina Kharchaf

International Journal of Nuclear Security

Nowadays, a security regime for protecting nuclear and radiological material—providing an intelligent national regulatory institution and establishing national security laws—is necessary in order for a state to ensure security of nuclear and radiological materials used within its borders.

This paper focuses on discussing the opportunities and challenges facing the future of nuclear security after the creation of the new Moroccan Agency of Nuclear and Radiological Safety and Security.

Impact Of Flow Direction On Local Flow Behavior In Biologically-Inspired Flow Passages, Derrick Dewayne Herrin

Honors College Theses

ABSTRACT

A computational fluid dynamics model was utilized to study the effect of flow direction on local flow behavior in biologically-inspired microscale flow networks. Biologically-inspired flow networks have been found to offer numerous advantages when compared with parallel flow networks, particularly in thermal management applications. Flow behavior was examined for a range of bifurcation angles and laminar inlet Reynolds numbers. The computational model was validated with existing theoretical solutions and verified for grid independence. As the bifurcation angle increased, the pressure drop, and thus pumping power, across the biologically-inspired flow networks increased. In addition, as the inlet Reynolds number increased, …

Strength Analysis For The Rudders Of Power-Free Underwater Vehicle In Kuroshio Subjected To Typhoon Waves, Chuan-Tsung Lee, Ray-Yeng Yang, Huang Hsing Pan, Li-An Kuo

Journal of Marine Science and Technology

In this study, a 1/25 hydraulic model of a power-free vehicle was developed. Typhoon waves and Kuroshio current flow in a wave-current flume (200 x 2 x 2 m3 ) were applied to the model for determining the net flow velocity and mooring forces. Through hydraulic experiments with a wave period of 16 s, wave height of 10 m, and ocean current speed of 1.0 m/s, a net flow velocity of up to 3.81 m/s was measured. The maximum lift and drag forces acting on each rudder were calculated through computational fluid dynamics as -245.6 and 151.6 kN, respectively, when …

Experimental Study Of Dynamic Stability Of Underwater Vehicle-Manipulator System Using Zero Moment Point, Jin-Il Kang, Hyeung-Sik Choi, Mai The Vu, Nguyen Ngoc Duc, Dae-Hyeong Ji, Joon-Young Kim

Journal of Marine Science and Technology

For manipulative underwater operations, an underwater vehiclemanipulator system (UVMS) has more degrees of freedom than those required to conduct a given mission. To follow the desired end-effector position and velocity accurately, UVMS should be able to generate trajectories of manipulators and the underwater vehicle can maintain dynamic stability of the entire system. In this paper, redundancy resolution is performed to find a solution satisfying the given task among many joint-space solutions. Also, to improve the dynamic stability of the UVMS, zero moment point (ZMP) is adopted such that it requires some constraints. For application of UVMS, a joint limitation is …

Characterization Of Structural Dynamics Of The Human Head Using Magnetic Resonance Elastography, Andrew Arun Badachhape

McKelvey School of Engineering Theses & Dissertations

In traumatic brain injury (TBI), the skull-brain interface, composed of three meningeal layers: the dura mater, arachnoid mater, and pia mater, along with cerebrospinal fluid (CSF) between the layers, plays a vital role in transmitting motion from the skull to brain tissue. Magnetic resonance elastography (MRE) is a noninvasive imaging modality capable of providing in vivo estimates of tissue motion and material properties. The objective of this work is to augment human and phantom MRE studies to better characterize the mechanical contributions of the skull-brain interface to improve the parameterization and validation of computational models of TBI. Three specific aims …

Comparison Of The Bi-Directional Performance Of Micro-Channel Sieve And Thin-Film Time Peripheral Nerve Interfaces, Robert Coker

McKelvey School of Engineering Theses & Dissertations

Sophisticated motorized prosthetic limbs contain multiple degrees of freedom of motion as well as embedded pressure and angle transducers to provide sensory feedback in amputees. Although several central neural recording and stimulation modalities exist for both controlling these motions and providing sensory feedback from a prosthetic limb, directly interfacing the peripheral nerves which originally innervated the limb has many advantages. A difficulty with this bi-directional approach is that electrically stimulating axons to provide haptic feedback creates stimulation artifacts at neighboring recording sites within the nerve that are several orders of magnitude larger than the electroneurogram used for control. In this …

System Characterizations And Optimized Reconstruction Methods For Novel X-Ray Imaging, Huifeng Guan

McKelvey School of Engineering Theses & Dissertations

In the past decade there have been many new emerging X-ray based imaging technologies developed for different diagnostic purposes or imaging tasks. However, there exist one or more specific problems that prevent them from being effectively or efficiently employed. In this dissertation, four different novel X-ray based imaging technologies are discussed, including propagation-based phase-contrast (PB-XPC) tomosynthesis, differential X-ray phase-contrast tomography (D-XPCT), projection-based dual-energy computed radiography (DECR), and tetrahedron beam computed tomography (TBCT). System characteristics are analyzed or optimized reconstruction methods are proposed for these imaging modalities. In the first part, we investigated the unique properties of propagation-based phase-contrast imaging technique …